I'll try to say a few words to you here but by rights you should have your own thread -this here is one for technical questions, not about people.
If you are unsure how to make your own thread see the very first post in this FAQ thread here, Sophie_M explains what to do
(If you get stuck sing out)
OK, now for your circumstances: it looks to me like you are trying to get everything done you possibly can in your life, HSC for oyur future plus 2 jobs for the money.
If I had to choose I'd say anything that made your HSC more difficult should be shelved for a while, and if your mum agrees then I guess that might be a pretty good indicator.
Getting stressed right when you need study time and concentration seems to me to be counter-productive. I found HSC hard enough to need my full attention plus study.
If cash gets short can your mum help out -or even your sister?
It sounds like I'm telling you waht to do, I"m not, just trying to put myself back in time in your shoes and see the priorities - you may well disagree, or have other factors to consider we have not talked abut.
I'd like to know what you think (preferably in a new thread)
When you do make a new thread give some thought to the title as that is what lets people know what to expect.
I hope to hear from you soon
Croix (who did not enjoy HSC either but got there in the end)